By Takehiro Sueki

V. 24 (1974)

pp. 349-362

Hawaii, USA

p. 349

It is often said that Japan has never had any logic and that her philosophy has always been irrational. Certainly Japan has never had any formal logic, and although she once imported Indian formal logic (hetu-vidyaa, In-Myoo) in the eighth century, it remained undeveloped. Nonetheless it is still wrong to hold that all of Japanese philosophy is irrational. On the contrary, there have been many rational thought structures in Japan, although their creators did not formulate an explicit, formal logical frame.

I will attempt to investigate a mode of rationalism which can be found in Tokugawa Japanese thought. To state the conclusion first: Japanese rationalism has some peculiar features which cannot be seen in the West but which are common to other Eastern thought structures. These features may be enumerated as follows:

(i) there is no substance which can exist by itself -- substancelessness;

(ii) so, all entities are relative to one another -- mutual dependence;

(iii) this relation of mutual dependence can be formalized with a special formula of equivalence. The result may be called a special sort of dialectic, that is, a nonsubstantial nonprocessive dialectic.

I will try to explicate these features of Japanese rationalism through an analysis of a particular philosophical structure, the philosophy of. Sontoku Ninomiya.

Ninomiya (1785-1856) was a contemporary of Schopenhauer (1788-1860) in Germany, of Comte (1789-1857) in France, and of Carlyle (1795-1881) in England. He is one of the greatest rationalists that Japan has ever produced and he is also famous for having been a man of action. He has been called the "Peasant Sage of Japan" because he relieved thousands of people from suffering caused by the famines which struck from time to time. He not only helped them to reestablish themselves economically but morally as well. He was the first economist in Japan to recognize the law of economic reproduction which Quesnay (1694-1774) had made clear in his Tableau Economique. He was also the first scientist in Japan who recognized the law of evolution which Darwin (1809-1882) established in his On the Origin of Species. What made him particularly famous was his economico-moral theory, which has been termed the "Economy of Thanks" (or repayment of virtue) (hootoku).

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The purpose of this article is to analyze the logical form of his fundamental philosophical view. As a preliminary step, we will survey briefly his theory of the "Economy of Thanks." He asserts:

(i) that the first principle of all human action is egoistic desire;

(ii) but that if we try to satisfy our own egoistic desires without reserve, then we will necessarily be in conflict with one another;

(iii) and that if we clash with one another, then we cannot fully satisfy our own desires, so that the unlimited egoism contradicts itself;

(iv) thus that we ought to control our own desires, if we want to gratify our own desires satisfactorily (but not unlimitedly).

This reasoning, which might be called enlightened self-interest, is similar to that of Hobbes (1588-1679). But Ninomiya does not assert a theory of the social contract as Hobbes did.

According to Ninomiya, we not only ought to control our own desires but also give others part of our own property. This is a sort of mutual-aid (suijoo) theory. There are many philosophers who advocate a theory of mutual aid, but the characteristic of Ninomiya's theory lies in the fact that it was founded on gratitude for the benefits recovered from others. He asserts that we cannot live utterly alone, because we are all so imperfect that we must depend upon others to maintain our life. Without help from others, we cannot live even for a minute. Just as, if there is no food we cannot sustain our life, or if there is no air we cannot breathe.

Thus, he argues both egoism and mutual dependence are the two basic principles on which our life is based. They are two indispensable conditions for the sustaining of life. If we want to maintain our life, then we must accept both of these principles; we must restrain our egotistic desires by recognizing the necessity of mutual aid. Thus, his theory of mutual aid, that is, the "Economy of Thanks," was formulated to introduce harmony between egoism and altruism. He tried to formulate this concept of harmony in a logical form, which we will analyze later.

His "Economy of Thanks" can be summarized as follows:

(i) It is the harmony between egoism and altruism.

(ii) In its practical application, it is a planned economy which sets a standard for one's income, which is determined by averaging one's previous yearly incomes. This standard then serves as a basis for the regulation of our labor, expenditure, and savings.

(iii) The most characteristic feature of his theory lies in the manner in which the usage of savings is regulated in the light of the standard. Specifically, he tells that we ought to transfer a certain percentage

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of our savings to others for their welfare, that is, we should contribute to a social welfare fund because it is our duty to return the favor granted us by others (even if the ultimate recipients are not the persons who directly helped us).

Thus in Ninomiya's view, there is no economy without morality, nor morality without economy.

He founded his economico-moral theory on his basic philosophical stance which is termed the theory of "Relative Monism" or "Duality." This theory can be summarized as follows.

He argues that self-reflection is a precondition of the establishment of a rational, stable, and satisfying lifestyle. By means of such self-reflection we will realize that a human being is essentially a unity founded on the mutual dependence of mind and body. This mutual dependence Ninomiya calls 'Duality' (nigen) in the general case, or corpo-mental duality in this instance.

This notion of duality is not identical with Descartes' dualism. For Descartes asserts that there are two substances, mens and corpus, which are mutually independent, while, on the contrary, Ninomiya advocates that neither mind (mens) nor body (corpus) is an independent substance. He argues that they are mutually dependent factors which are inseparably connected. Thus there is no mind without body, nor body without mind.

Nor is his theory similar to that of Spinoza. According to Spinoza, though mind and body coexist, they are independent of each other, while Ninomiya asserts that they are dependent on each other. Moreover, Ninomiya holds that we will recognize duality of human action and Nature, if we extend our self-reflection from the confines of our individual corpo-mental duality to the universe. This general relation Ninomiya calls 'naturo-human duality' (the Way of Heaven and the Way of Man). Just as every individual is a unity based on the mutual dependence of body and mind, so too human culture is based on the mutual dependence of Nature and human action.

Thus, duality is the first principle of all the phenomena we perceive. The two factors which constitute the duality are contrary to one another, but they are yet combined so inseparably with each other that they can also be said to constitute a unity (ichigen). This is the logic of duality. Day and night, for instance, are contrary to each other, but since they are combined so inseparably with each other they constitute one full day as their union. Both nature-human duality and corpo-mental duality are particular cases of duality. Indeed his theory of economico-morality is also based on this principle of duality; although egoism and altruism are two factors contrary to each other, they are combined

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so inseparably with each other that they do constitute an economico-moral unity.

His theory of naturo-human duality can be further developed as follows:

(i) The two factors, Nature and human action, constitute a cultural world by forming a tight union.

(ii) Nature and human action depend on each other. So, there is no Nature without human, action, no human action with Nature.

(iii) Neither Nature nor human action is a substance which can exist by itself.

(iv) Nature and human action are in opposition to each other, so that they each have different functions.

(v) The principal features of Nature are as follows:

(v-l) It has no purpose or evaluative differentiation.

(v-2) It is arranged in a spatio-temporal form, and the temporal form is not reversible.

(v-3) All entities in Nature are mutually dependent in the causal nexus, that is, every entity is a result of other entities which act as causes, and each becomes, in turn, a cause of other entities, which result from its action.

(v-4) This causality always forms a cyclic system, for example, seed --> grass --> flower --> fruit --> seed.

(v-5) This cyclic system is not a simple repetition of the same phenomena but changes progressively, so that Nature evolves continually from a simple to a more complex state.

(v-6) In Nature all entities are ceaselessly changing, but the whole which they compose remains always unchanged.

(vi) The principal feature of human action are as follows:

(vi-1) Men select certain purposes and aim at achieving them.

(vi-2) They evaluate things according to their purposes.

(vii) Human action recognizes some parts of Nature and rejects others according to a criterion of evaluation, which is constructed in accord with the selected purposes. Thus we can transform Nature purposively. The result of this purposeful activity is our culture. In other words, our cultural world is a. concrete example of naturo-human duality.

We must observe the laws of Nature if we would transform Nature purposively. However, over and above this, corresponding to the laws of Nature, there must be practical rules. These constitute Ninomiya's system of economico-morality. They are:

(i) If we work in accordance with the irreversible order of time, then our labor becomes effective; but if we work without acknowledging this order, then our efforts cannot bring about any favorable result.

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(ii) We ought to give some part of our own property to others, because to aid others is to thank them for what they have done for us, even if our contribution is not given to those who directly benefited us. This "mutual aid of thanks" (suijoo) is based on the mutual dependence of all things. Since we are all mutually dependent, we can not recognize ourselves as human beings if we do not recognize others. To thank others for their favor to us is to recognize others as human beings in order to recognize ourselves.

(iii) We ought to be frugal and invest our savings in future production. Frugality and investment are sustained by causal cycle, since savings result from production and investment influences future production, which will in turn enable us to build future savings.

(iv) We ought to regulate our labor, expenditure, savings, investment and charity by the standard of average income. Both the establishment of a standard and its regulation are derived from the principle of the unchangeability of the whole. For, to set one's standard of income on the basis of the average of the previous income is to assume an unchangeable whole encompassing the seemingly random variations in yearly income.

(v) We can make our income increase if we conform to the direction of evolution in Nature.

(vi) Thus, we can transform even Nature purposively, if and only if we observe the laws of Nature.

Finally, Ninomiya teaches that we must awaken spiritually in order to gain true understanding about the world and lead a truly rational and moral life. (i) This spiritual awakening is nothing but the realization of emptiness of all the phenomena in the world. (ii) According to Ninomiya, there is no enduring substance behind phenomenon, which means that all things arise out of emptiness and disappear into emptiness. Thus there are no absolute values in the world, for each thing disappears into emptiness, giving no support to a constancy of value. (iii) There is no absolute distinction between good and evil, precisely because there is no absolute value. The distinction between good and evil can be applied only relatively, since value can only be determined in terms of the relation of one phenomenon to another. What is evaluated as good from one point of view may be evaluated as evil by another. What is good for a cat is evil to a rat; what is good for a winner is evil to a loser. (iv) This means that spiritual awakening is the realization of the relativity and emptiness of all phenomena in the world. Ninomiya's entire theory is based on this principle of relativity which he termed 'duality'.

His philosophical system can be analyzed and arranged as follows: (i) realization of emptiness of all things in the world; (ii) realization of relativity or duality of all things which is based on (i); (iii) realization of naturo-

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human duality which is a special and concrete form of this relativity or duality; (iv) economico-moral practice termed the "Economy of Thanks," which is based on this realization of naturo-human duality; and finally, (v) all these factors can be connected to one another through self-reflection.

The interrelationship of these factors is illustrated by the following diagram:

Ninomiya's system is so thoroughly rational that it can be analyzed in terms of formal logic. I hope my analysis will clarify not only the fundamental terms of Ninomiya's system but also the characteristics of a typical pattern of Japanese thought. (The symbolic logic which we shall use here is that of Whitehead-Russell's Principia Mathematica.)

The fundamental terms of Ninomiya's system are 'emptiness' and 'duality.'

At first I will analyze the term 'duality'.

The two concepts which constitute duality must fulfill the following two conditions: (i) they are contrary to each other; that is, they are converse functions; (ii) they are necessary conditions for each other. For example husband and wife are dual. For, if a person x (male) is a husband of another person y (female), then x is not a wife of y. This means that the two concepts husband and wife, are mutually exclusive, or not compatible.

Suppose 'h (x, y)' denotes 'x is a husband of y, and 'w (x, y)' denotes 'x is a wife of y. Then, if h (x, y) is true, then w (x, y) is not true. That is to say,

h (x, y) w (x, y) (F 1.1)

which can be transformed as follows:

~ [h (x, y)ĦEw (x, y)]. (F 1.2)

This formula reads: x cannot be both a husband and a wife of the person y.

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In other words, the two concepts, h and w, are mutually exclusive, or not compatible.

These two concepts are interdependent, or they are necessary conditions for each other. For, if x is not a husband of y, then y is not a wife of x, and vice versa. That is,

[~h (x, y) ~w (y, x)]ĦE[~ w (y, x) ~h (x, y)]. (F 2)

which can be simplified as

h (x, y) w (y, x) (F 3)

This -formula reads: h (x, y) and w (y, x) are necessary conditions for each other. Thus, the two concepts, husband and wife, are dual, because they fulfill the two conditions of duality.

If we express 'duality' with such a sign as

x, y, (F 4)

then duality of h and w can be expressed as

h (x, y)w (y, x) (F 5)

which can be defined as follows:

h (x, y)w (y, x) = df ~ [h (x, y)ĦEw (x, y)]ĦE[h (x, y) w (y, x)] (F6)

Another example of this principle is the following:

Ninomiya thinks that our mind and body are dual. For (i) our mind is a moment to unify the multiplicity of our body, and vice versa. So, suppose. 'M' denotes 'our mind', 'B' 'our body', 'un (x, y)' does 'x unifies y', and 'mu (x, y)' 'x reduces y to a multiplicity'. Then

~[un (M, B)ĦEmu (M, B)]. (F 7)

This formula reads: our mind does not at the same time unify our body and reduce it to a multiplicity. (ii) These two concepts, unity and multiplicity in regard to our mind and body, are interdependent; they are necessary conditions for each other. For, if there is no unification of our mind as opposed to our body, then there is no multiplicity of our body as opposed to our mind, and vice versa. This relation can be formulated as follows:

[~ un (M, B) ~ mu (P, M)]ĦE[~ mu (B, M) ~ un (M, B)], (F8)

which can be simplified as

un (M, B) mu (B, M) (F9)

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This formula reads: un (M, B) and mu (B, M) are necessary conditions for each other.

Thus, the two concepts, unity of mind as opposed to body and multiplicity of body as opposed to mind, are dual, because they fulfill the two conditions of duality. Namely,

un (M, B)mu (B, M) (F 10)

which can be defined by conjunction of (F 7) and (F 9):

~ [un (M, B)ĦEmu (M, B)]ĦE[un (M, B) mu (B, M)]. (F 11)

Generally speaking, two concepts P and Q, which are both binominal predicates, are called dual, that is,

P (x, y)Q (y, x) (F 12)

if they fulfill the following two conditions:

(i) P and Q are mutually exclusive with respect to the same ordered couple, that is to say,

~ [P (x, y)ĦEQ (x, y)]; (F13)

(ii) P and Q are necessary conditions for each other with respect to the converse arguments, that is,

P (x, y) Q (y, x). (F14)

Thus, we can define 'duality' of the two concepts as

P (x, y)Q (y, x) = df ~ [P (x, y)ĦEQ (x, y)]ĦE[P (x, y) Q (y, x)] (F15)

In this definition we can say that x and y, as well as P and Q, are dual.

Ninomiya thinks that everything in the world has the relation of duality to something other than itself -- this is one of his fundamental theses.

Suppose, 'W' denotes 'the world or the universe of all things.' Then the thesis means that everything x which belongs to W is an argument of some dual concepts in respect to a certain thing y which belongs also to W and is not identical with x, namely,

(x) {xW) (y) ( ) () [((x, y)(y, x))ĦE(yW)ĦE~ (x=y)]} (F16)

According to the thesis, everything in the world must be dual to some other thing in the world, but Ninomiya gave special attention to two particular instances of duality, namely, the duality of mind and body, and that of Nature and human actions.

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As for the former, we have already formulated it as an example of 'duality', it was

un (M, B)mu (B, M). (F 10)

As for the latter, that is, as for duality of Nature and human action, we can similarly formulate it as follows. Suppose, 'N' denotes 'Nature', 'H' 'human actions,' 'un' denotes 'unification', and 'mu' 'multiplicity.' Then, duality of Nature and human action (naturo-human duality) can be expressed as

un (H, N)mu (N, H). (F 17)

This formula can be analyzed as follows:

(i) ~ [un (H, N)ĦEmu (H, N)], (F 18)

which denotes incompatibility or mutual contrariness of unification and multiplicity in respect to Nature and human action;

(ii) un (H, N) mu (N, H), (F 19)

which denotes that unity of human action as opposed to Nature and multiplicity of Nature as opposed to human action are necessary conditions for each other. This analysis is based on the definition of the earlier mentioned duality (F 15). Ninomiya's practical theory can be derived from this principle of naturo-human duality (F 17).

According to the thesis (F 16), everything in the world must be dual to some other thing in the world. Thus, everything in the world must be dependent on some other thing in the world since the duality of two things implies their mutual dependence. This is to say that if two things are 'mutually dependent,' they are necessary conditions for each other. As was discussed previously, the concepts of husband and wife are dual. They are mutually dependent, because there is no husband without a wife, nor wife without a husband. Formally expressed, it is

[h (x, y)w (y, x)] {[~ w (y, x) ~ h (x, y)]ĦE[~ h (x, y) ~ w (y, x)]} (F 20)

This formula denotes the same thing as

[h (x, y)w (y, x)] [~ h (x, y) ~ w (y, x)] (F 21)

or by the contraposition of (F 21), it can be rewritten

[h (x, y)w (y, x)] [h (x, y) w (y, x)]. (F 22)

Just as the formula (F 22) can be derived from the definition of 'duality' (F 15), 'mutual dependence' can be drawn from 'duality.'

Suppose in general 'd (p, q)' denotes 'a proposition p depends on another

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proposition q,' and 'md (p, q)' denotes 'the two propositions p and q depend upon each other.' And we define these concepts as follows:

d (p, q) = df (p q) (F 23)

md (p, q) = df (p q)ĦE(q q) (F 24)

In other words, the dependence of a proposition p upon another proposition q means that q is a necessary condition for p; and the mutual dependence of p and q means that p and q are necessary conditions for each other.

Further, if d (f (x), g (y)) holds, then we can also say that x is dependent upon y in respect to f and g. Similarly, if md (f (x), g (y)) holds, then we can also say that x and y are mutually dependent upon one another in respect to f and g. These can be formulated as:

df,g (x, y) = df (f) (g) d (f (x), g (y)) (F 25)

mdf,g (x, y) = df (f) (g) md (f (x), g (y)), (F 26)

Hence we can obtain the relation between duality and mutual dependence, that is,

[f (x, y)g (y, x)] md [f (x, y), g (y, x)] (F 27)

It can be easily derived from (F 15) and (F 24). Further, if we simplify 'f (x, y)' as 'f' (x)', and 'g (y, x)' as 'g' (y)', then we can say that

[f (x, y)g (y, x)] mdf',g' (x, y) (F 28)

Now we can proceed to analyze the term 'emptiness,' which is one of Ninomiya's fundamental terms. By 'emptiness' we mean substancelessness. By 'substance' we mean an independent entity, that is, an entity which depends only upon itself. So, by 'substancelessness' we mean the claim that there are no independent entities. Thus, 'emptiness of a thing' means the negation of its independence. But 'independence' is nothing but the negation of 'dependence', which has been defined. So, the 'emptiness of a thing' can be defined symbolically as follows.

Suppose, 'id' denotes 'independent', and 'emp' 'empty,' then:

id (x) = df

(f)
(g) (y)
[~ (x = y) ~ d (f (x), g (y))]. (F
29)

Any independent thing does not depend, upon anything other than itself in respect to any concept.

emp (x) = df ~ id (x) (F 30)

This is the definition of 'emptiness,' which reads: emptiness of a thing means that it is not independent.

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From the theorems (F 16), (F 27), (F 28), and the definition (F 30), it can be easily derived that everything in the world is empty. First, from (F 16), (F 27) and (F 28) it is held that

(x)
[(xW)
(f) (g)
(y)

md (f (x, y), g (y, x))], (F 31)

and also that

(x) [xW] (f') (g') (y) mdf',g' (x, y)]. (F 32)

Since formula (F 32) reads: all things in the world are mutually dependent, it means that from (F 32), (F 29), and (F 30), we can obtain the expression

(x) [(xW) emp (x)]. (F 33)

This formula, denotes that all things in the world are empty.

We have now analyzed and formulated the fundamental terms of Ninomiya's system of thought. As a result we can see that his philosophy is based on the theorems (F 16), (F 32), and (F 33). These theorems are:

(i) duality of all things (F 16);

(ii) mutual dependence of all things (F 32);

(iii) emptiness of all things (F 33).

(The second principle (F 32) is, strictly speaking, only a corollary of (F 16), but it is of a great importance, so it may rightly be treated as a principle of his philosophy.)

Now we will analyze briefly some of the fundamental terms of Ninomiya's practical theory. His theory of "Economy of Thanks" is based on the term 'mutual aid' (suijoo). This term is, in turn, based on the term 'mutual dependence' which has been already defined. Suppose, 'ma' denotes 'mutual aid', and 'per' 'a person'. Then,

ma (x, y) = df

per (x)ĦEper (y)ĦE(f)
(g) mdf,g
(x, y) (F 34)

which reads 'mutual aid' is defined as the mutual dependence of two persons x and y in respect to some concepts f and g. According to theorem (F 32), all things in the world must be mutually dependent. So, all persons must be related in terms of mutual dependence, or, in other words, they are in the relation of mutual aid with one another. This can be expressed as follows:

(x) [per (x) (xW)] (F 35-1)

(x) (y) [per (x)ĦEper (y) ma (x, y)] (F 35-2)

This is an application of (F 32).

The relation of mutual aid between any two persons implies their mutual dependence, and their mutual dependence implies their biconditionality (F 24,

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F 26), so any two persons must recognize each other as being in this relation, if they want to live in peace. This can be expressed as follows:

(x) (y) {per (x)ĦEper (y) (f) (g) [f (x, y) g (y, x)]} (F 36)

(This formula can be easily derived from (F 35), (F 34), (F 26), and (F 24)).

If one of them, say x, negate the relation f to the other, say y, then by taking the contraposition of their mutual recognition (F 36), y also has the right to negate the relation g to x. This results ultimately in the mutual negation of the two persons. In such a relation they cannot live in peace. This is the state of bellum omnium contraonmis, which can be formulated as follows:

(x) (y) {per (x)ĦEper (y) (f) (g) [~ f (x, y) ~ g (y, x)]. (F 37)

As a practical method for mutual recognition (F 36), Ninomiya urged his theory of charity. The essence is that one must first of all recognize or acknowledge the humanity of other people if one wants to be recognized oneself, and further the recognition of others implies a duty to give a portion of one's possession for the benefit of others.

There still remain many terms to be analyzed, but at present we must leave them unanalyzed because there is not enough space for that here. Instead let us go on to another problem, that is, a comparative philosophic explanation of Ninomiya's thought.

We will attempt to further clarify his fundamental terms -- duality, mutual dependence, emptiness, and mutual aid -- by comparing them with similar concepts which appear in other philosophical systems.

Ninomiya teaches the duality of all things, which was formulated as (F 16). This theory of duality seems to conform to the tradition of Confucianism. According to one of Confucian classics, the I-Ching, all things in the world have a positive or negative relation to one another, that is, the celebrated theory of 'the negative and the positive principles' [yin-yang]. One might express this in symbols in the following way. Suppose, 'P (x, y)' denotes 'x is positive for y,' and 'N (x, y)' 'x is negative for y.' Then, x cannot be both positive and negative with respect to y. That is, P (x, y) and N (x, y) cannot be compatible.

~ [P (x, y)ĦEN (x, y)]. (F 38)

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It is also said that x is positive for y, if and only if y is negative for x, that is,

P (x, y) N (y, x). (F39)

From (F 38) and (F 39), it can be derived that

~ [P (x, y)ĦEN (x, y)]ĦE[P (x, y) N (y, x)] (F 40)

which means nothing but the duality of P and N.

This means that Ninomiya's theory of duality belongs to the tradition of Confucianism in the sense that the basic Confucian concepts exemplify the logic of duality.

The theorem of mutual dependence (F 31) is derived from the theorem of duality as was shown earlier. On this point also, Ninomiya's thought follows the tradition of Confucianism. The concept of the 'mutual dependence of all things,' however, is also one of the fundamental principles of Buddhism. Buddhism asserts that there is no independent substance in the world, and that all things necessarily depend upon one another (paratantra-svabhaava). Thus, on this point, Ninomiya's theory of mutual dependence partakes of the tradition of Buddhism, as well as that of Confucianism.

As was discussed earlier, the mutual dependence of all things is equivalent to emptiness of all things. Ninomiya asserts that all things in the world are mutually dependent (F 32), so that all things in the world are necessarily empty (F 33). But this theorem of the emptiness of all things is also one of the fundamental theorems of Buddhism. Buddhism asserts that all things in the world are mutually dependent; they are not independent substances. In Buddhism, this is termed 'emptiness' (`suunyataa; kuu shoo). Thus, it is clear that Ninomiya's theory of emptiness also belongs to the tradition of Buddhism.

Ninomiya's practical philosophy is based on the theorem of 'universal mutual aid', (F 35). But this theorem can be derived from that of 'mutual dependence', which belongs to the tradition of Buddhism, as well as to that of Confucianism, as we have shown. Thus, his practical philosophy conforms to both traditions. Further, his theorem of mutual negation (F 37), which is a corollary of the theorem of mutual aid (F 35), is very similar to Han

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Fei's philosophy. But Han Fei does not assert mutual recognition. (F 36 ). On this point Ninomiya is quite different from Han Fei.

To summarize, the fundamental theorems of his thought are based on the orthodox traditions of Confucianism and Buddhism. It is true that he adds some original theories of his own, especially those concerning natural philosophy and economy. But all these original theories are based on his theorems of duality, mutual dependence, emptiness, and mutual aid -- all traditional concepts of Confucianism and Buddhism. Thus, we can say that his philosophy is a rationalistic development of traditional Eastern thought. Eastern thought is usually said to be irrational. But in truth, its core is thoroughly rational, although the pattern of its rationalism is different from that of the West. Ninomiya developed fully this rationalistic moment of the Eastern thought in his own original way.

Finally, it would be instructive to make a comparison of his theory of 'duality' with Hegel's dialectic.

'Duality' means the identity (equivalence) of mutually exclusive concepts, (F 15). That is, the formula (i) ~ [P (x, y)ĦEQ (x, y)] expresses mutual exclusiveness of the two concepts, P and Q. (ii) P (x, y) Q (y, x) expresses identity (equivalence) of these mutually contradictory concepts. Thus, 'duality' is the basis of a sort of dialectic; since the term 'dialectic' usually means a logical relation of identity of two concepts taken to be contrary to each other. But the 'duality' of Ninomiya is not the same sort of dialectic as that of Hegel. Consider the salient points of these two dialectics.

First, Hegel's dialectic has the two characteristics: (a) it presupposes existence of a substance, which Hegel calls 'the absolute spirit' (der absolute Geist); (b) his dialectic is a process of self-development of this single substance.

So, Hegel's dialectic can be called a substantial processive dialectic.

On the contrary, Ninomiya's duality (a) presupposes no independent substance, and therefore (b) it is not any process of self-development of the single substance.

His duality is no substantial processive dialectic. It would have to be characterized as nonsubstantial nonprocessive dialectic, if we wanted to call it dialectic.